Perturbation theory for double-time temperature-dependent Green functions
- 1 October 1962
- journal article
- research article
- Published by Taylor & Francis in Advances in Physics
- Vol. 11 (44), 317-348
- https://doi.org/10.1080/00018736200101312
Abstract
A perturbation theory is developed for normal many-particle systems by expanding the inverse of the advanced and retarded Green functions. Both systems with direct interactions and systems with interactions through a quantum field are considered. For the former, the infinite set of coupled equations is written down and the various methods of decoupling discussed. Systems with weak, hard sphere type, or coulomb interactions are considered and the connections with other methods discussed. For systems with quantum field interactions, the chain of equations involves both fermion and boson Green functions and the first approximation can be much better than in earlier cases. This latter approach seems to be more convenient when collective oscillations are important.Keywords
This publication has 3 references indexed in Scilit:
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- Theory of Many-Particle Systems. IPhysical Review B, 1959
- Un développement du potentiel de gibbs d'un système quantique composé d'un grand nombre de particulesNuclear Physics, 1958